A new study published in Nature Communications has revealed how single changes to the chemical compounds that control our DNA (known collectively as the epigenome) can set off a chain of events that could cause healthy breast cells to become abnormal, and potentially develop into tumours.

The discovery brings researchers a step closer to unravelling how these small changes can lead to the development of breast cancer.

Using cells from the Breast Cancer Now Tissue Bank, researchers led by Dr Gabriella Ficz at Queen Mary University of London used the cutting-edge CRISPR-dCas9 gene editing technique to target the epigenome –– rather than the genome itself – meaning that none of the cells’ inherent DNA code was altered.

The epigenome acts as an ‘on/off’ switch for our genes, and the researchers found that flicking the ‘epigenetic switch’ of a single gene caused rapid cell division and prevented breast cells from carrying out the natural processes by which they would normally age and die (known as senescence). They identified that this alone might be responsible for initiating tumour formation in previously healthy breast cells.

“The use of CRISPR to edit the epigenome of breast cells is an exciting advance, and one that could provide a much greater understanding of how the activity of individual genes can cause healthy breast cells to become cancerous.

“Understanding the epigenetic changes that take place inside breast cells could allow us to pinpoint – at a very early stage – cells that have become abnormal and might develop into breast tumours. Dr Ficz’s research could one day lead to new therapeutic targets, as well as biomarkers that could ensure the disease is diagnosed and treated as early as possible, giving patients the best chance of survival.

“Research using human breast tissue is vital, and the Breast Cancer Now Tissue Bank exists to ensure that the most promising studies – like Dr Ficz’s – are able to access to high quality tissue samples which can be used to advance our knowledge of this devastating disease.”